The common "western diet" is known to cause obesity, diabetes, stroke and other serious conditions over time. However, new research shows that unhealthy diets due to high refined sugar and saturated fats can lead to a breakdown of cognitive function.

Davidson says, "One of the basic protections of the brain is an area called the blood-brain barrier. When it breaks down things get into the brain that don't belong."

This is especially a big deal for the hippocampus, the spot in the brain responsible for learning and memories. This makes it harder for an obese person to put away thoughts about the unhealthy foods that are consumed on a regular basis.

Davidson says, "Food is a very powerful memory, very powerful in our lives. If we reduce this inhibitory abilityit's going to be more likely that those things are going to be on your mind more."

Davidson adds, "You're going to respond more in your food cues in your environment that remind you of those certain things and that can lead to overeating."

This can undermine efforts to move towards a healthier diet and preventing future problems like stroke, diabetes, high blood pressure and heart attack.

Davidson says, "Its almost like you remember too much."

The study included research from Purdue, the University of Texas Southwest Medical Center, and the Medical School of the University of Cincinnati.